A healthy living blog from Marshfield Clinic

Gender prediction: Can you believe the wives’ tales?

When you find out that you’re having a baby, one of the first things people want to know is the due date; second  is the gender. And then you may hear people say things like, “I heard that if … you are having a boy. Or, by the look of how you are carrying … it’s a girl.”

Photo of a gender reveal cake

Although gender predictions are fun, you won’t have 95% accuracy until the anatomy screening is completed at 20-some weeks pregnant.

You may be bombarded with several prediction methods as to what gender you are having. So what can you believe?

Women’s health providers at Marshfield Clinic Health System can help explore gender reveals and how to tell the sex of your baby.

Revealing baby’s gender

In recent years, you see parents hosting gender reveal parties with colorful confetti or powder, smashing pink and blue eggs on their heads, or simply cutting a cake to find out the baby’s sex.

Prior to the celebration, obstetrics and gynecology (OB/GYN) providers work with ultrasound technicians to determine the gender of the fetus.

“We don’t order ultrasounds for gender but we order an anatomy screen at about 20 weeks at which time patients often find out gender,” said Nanette Boehm, certified nurse midwife. “Although, I have noticed a significant trend back toward not finding out the gender.”

Dr. Barb Coulter-Smith, OB/GYN physician, said you could sometimes determine gender as early as second trimester, but reliably by 18 to 20 weeks. End of the first trimester testing has 80% accuracy and the 20-week anatomy screening has 95% accuracy. If you have a cell-free DNA chromosome aneuploidy screening (report of actual sex chromosomes of the fetus), that will offer 99% accuracy.

Options to determine gender

During the second trimester, parents have a few options to know the gender, but more importantly, check on baby’s health. Most of these options are not elective, as your midwife or doctor will recommend the test. These options include:

A cell free or noninvasive prenatal test (NIPT) can determine the gender by 9-10 weeks. This is a blood test after 10 weeks and generally not considered elective. It can detect some chromosomal abnormalities like Down syndrome as well as gender.

Lab testing includes types of genetic testing. One test,an invasive test called amniocentesis, is done around 15 weeks or later and needs to be medically necessary and because it carries some risk. This sampling of amniotic fluid contains fetal cells that can be tested for genetic disorders and gender. This is not an elective test.

Chorionic villi sampling (CVS) is another invasive test for genetic abnormalities. Gender also can be identified. This is a sampling of placental material and carries risks. This is not an elective test.

Other gender predictions like “old wives tales” do not have scientific evidence to make them credible. Dr. Ben Faustich, OB/GYN physician, said studies, performed typically by medical students or in resident research projects, demonstrate that some specific methods like the heartbeat have no predictive value.

“None of the other methods have any evidence,” he said.

Are old wives’ tales for fun or dangerous?

Although in the United States prediction methods are mostly harmless, Faustich explains that in places like China and India, gender predictions have led to selective termination of female fetuses over the past 30 years.

“This is a significant social problem that will continue to become worse in the coming decades,” he said. “The introduction of ultrasound in those countries has led to an extreme imbalance of the sex ratio in adults, leading to a huge surplus of men. Nearly 1.4 men per 1 woman of reproductive age.”

Some gender predictions are just harmless fun and can lead to more excitement and anticipation of your bundle of joy.

Believe what you will, but turn to your provider for accurate health information for you and your baby.

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